<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>内置对象</title>
    <script>
        //parsefloat将字符串浮点数装换城浮点数
        document.write(Number.parseFloat("122.232")+"<br>");
        document.write(Number.parseInt("12")+"<br>");
        document.write(Number.isNaN(NaN)+"<br>");//Nan连自己都不可以进行比较

        //ceil向上取整
        //floor向下取整
        //round四舍五入
        document.write(Math.ceil(3.2222)+"<br>");
        document.write(Math.floor(3.222)+"<br>");
        document.write(Math.round(2.3)+"<br>");
        document.write(Math.random()+"<br>");

        //当前时间
        //
        document.write(Date()+"<br>");
        document.write(Date(2,4)+"<br>");
    </script>

</head>
<body>

</body>
</html>